Apparatus for lapping connecting rod ends, caps and similar articles



Sept. 29, 1953 F WHITE 2,653,423

APPARATUS FOR. LA'PPING CONNECTING ROD ENDS, CAPS, AND SIMILAR- ARTICLES Filed June 26, 1951 2 Sheets-Sheet l INVENTOR BY? M Z 7 3% Sept. 29, 1953 wHlTE 2,653,423

APPARATUS FOR/LAPPING CONNECTING ROD ENDS, CAPS, AND SIMILAR ARTICLES Filed June 26, 1951 2 Sheets-Sheet 2 INVENTOR %m( 75 m Patented Sept. 29, 1953 APPARATUS FOR LAPPIN G CONNECTING ROD ENDS, CAPS AND SIMILAR ARTICLES Fred L White, Chicago, 111., assignor to Crane Packing Company, Chicago, 111., a corporation of Illinois Application June 26, 1951, Serial No. 233,534

6 Claims. (01. 51-131) The present invention relates to lapping machines and more particularly to an apparatus for lapping connecting rod ends, caps and similar articles to a high degree of flatness. The invention is also concerned with a lapping machine fixture for holding such articles against a lap associated with a machine of the type disclosed in a co-pending application of Raymond G. Roshong, Serial No. 150,978, filed March 21, 1950, now Patent No. 2,627,144 dated February 3, 1953.

In the aforesaid Roshong application, there is disclosed a lapping machine comprising an annular lap on which are mounted one or more rings, the function of which is to dress the lap as the articles are being lapped. The rings, or wear rings as they are commonly termed, are held against revolution with the lap by means of rollers mounted on the ends of a curved bar extending partly across the lap surface and located in line with the direction of thrust of the rings. The interior of the rings is free for the reception of articles to be lapped.

Among the articles which it has been proposed to lap are connecting rod ends and the straps or caps for the connecting rods in order to promote perfect roundness for the crankshaft opening. As commonly made, the connecting rods and caps therefor are first broached to form the opening for the crankshaft and the split, and the cap and connecting rod are then assembled and the opening for the crankshaft pin is finish machined. The cap is then separated from the connecting rod and the connecting rod and cap are assembled with respect to the crankshaft. When the connecting rod and cap are assembled on the crankshaft, there is no assurance that they will assume precisely the same position they occupied when the opening for the crankshaft was machined. The breaching operation leaves the split somewhat rough. It frequently happens that the cap and connecting rod become slightly misaligned dueto the failure of the rough mating surfaces at the split to come together in exactly the same place. This results in a slightly oval condition in the opening which in turn decreases the efi'iciency of the engine.

It is the principal object of this invention to provide an apparatus for finishing the mating surfaces of a connecting rod and its cap in such manner that when the two are reassembled the opening for the crankshaft will be perfectly round.

A more specific object of this invention, in a lapping machine having a rotatable lap, is to 2 provide a fixture for lapping ends of connecting rods of the split type, the rods to be adapted to accommodate a large number of parts simultaneously whereby to secure a greater productivity for each operation.

A more specific object of this invention is to provide a work holder for connecting rods of a reciprocating engine which will serve to hold either the connecting rod or its strap on the lap.

A still more specific object of this invention is to provide a weight for holding the connecting rods on the lap while the connecting rods are being lapped, said weight being supported from the connecting rods through springs and being adapted to move vertically with respect to the surrounding wear ring, but at the same time being .locked to the wear ring so that it will rotate with the wear ring at all times.

Another specific object of this invention is to provide a wear ring for a lapping machine of the type described in the aforementioned Roshong application, said wear ring having mounted thereon a hollow tube or rod dispos in a Vertical position over the lap, a pressure plate for the connecting rods, said plate being keyed to the hollow rod so as to be slidable axially toward and away from the lap While being held against rotation relative to the wear ring, and a work holder having a pin which is received within the hollow rod so that the pin with its attached work holder are likewise compelled to rotate with the wear ring thereby insuring constant alignment for the openings in the work holder and pressure plate in which the connecting rods are retained.

These and other objects and features of this invention will become apparent from the following detailed description when taken together with the accompanying drawings, in which Fig. 1 is a plan view of a fixture made in accordance with thi invention; and

Fig. 2 is an elevation in section of the fixture taken along line 2--2 of Fig. 1.

Referring now to the drawings for a detailed description of the invention, there is shown a lap plate In such as is disclosed in the aforementioned Roshong application, said lap plate Ill being annular in form and provided with a plurality of radially disposed grooves II, the function of which is to remove the grit and cuttings from the surface of the lap as well as excess abradant. Said lap is preferably mounted in a horizontal position and is rotated at approximately fifty revolutions per minute. Mounted on the surface of lap I0 is a ring l2 which extends slightly beyond the inner and outer peripheries of the annular lap l0. Said ring is retained on the lap surface by means of rollers and a bar (not shown), the rollers acting upon the outer surface [3 of the ring. The details of construction of the rollers are disclosed in the aforementioned Roshong application and hence will not be detailed here. On opposite sides of the ring I2 are mounted substantially identical straps H to which is secured by welding or the like a rod l disposed on an axis which i perpendicular to the plane of lap ill. The straps I4 may be affixed to the upper annular surface of the ring 12 by suitable anchoring screws M. It is understood, of course, that rod I5 may be formed as an integral part of the strap 14, but for ease of manufacture, a fabricated construction may be desired.

Rod I5 is shown as having a square cross-section which is believed to be the best suited for this device, but it may have other cross-section shapes if desired.

Within ring I2 is a disc l8 which functions as the work separator or holder and which normally rests on the surface of the lap. Said disc 16 is formed with a plurality of openings I! into which the connecting rods or straps may be inserted. The shape of the opening I! is the same as the shape of the connecting rod end so that said connecting rod end may fit snugly in opening I! but at the same time will not be so snug as to prevent a slight amount of movement in the plane of the lap which may be necessary to secure proper alignment between the connecting rod and the other parts of the fixture.

The connecting rod is shown at Is and is provided with an enlarged end [9 which is semicircular in form and is provided further with bosses 2! and 22 into which the bolt hole are drilled. It will be noted that the connecting rod I8 is relatively long so that any rotation of the rod about the axis of ring l2 will result in a certain amount of centrifugal force in the free end of the connecting rod. This centrifugal force would tend to tilt the connecting rod relative to lap surface it and thus result in an undesirable sloped or possibly curved surface in the connecting rod end itself. It is necessary therefore to provide a holding means for the rods to prevent tipping.

The means for holding the connecting rod on the lap surface comprises a relatively heavy disc shaped plate 23 having a plurality of openings 24 through which the free ends of the connecting rods l8 project. Adjacent openings 24 are openings 25 in which are mounted pins 26. Each pin 28 has a cross pin 21 in its upper end and a conical-shaped point 23 at its other end. The conical point 28 is adapted to fit into the usual bolt hole 38 formed in the connecting rod. The conical ends 28 are constantly urged into the openings by springs 38 which are compressed by the weight of the plate 23, that is, the weight of plate 23 is carried by springs 38 and is transmitted by the springs or the connecting rods Hi. In this manner sufficient holding force is developed to resist any centrifugal force which might be present in the rods it.

It is apparent that the openings H in the work holder it and the openings 2 in the pressure plate 23 must always be in perfect alignment. If this were not so, then eventually either the work holder is or the pressure plate 23 would become displaced relative to one another and would then tend to tip the connecting rod with a resultant defective surface at the split.

The means by which the work holder it and pressure plate 23 are kept in alignment comprises a pair of pins 35 secured to work holder l6 and extending at right angles to the surface of the lap it. The rods which are secured to strap i4 and ring l2, are hollow at their lower ends as shown at 32 to receive pins 3!. In this manner work holder ES, pins 3!, rods l5 and ring 52 are compelled to rotate together at the same speed. Pressure plate 23 has formed in the outer periphery thereof diametrically opposed notches 34 each of which serves as a keyway for a rod 15. Notches 34 and rods l5 therefore constitute a means for preventing pressure plate 23 from rotating relative to rods i5. Since rods 45 are prevented from turning relative to work holder IE, the pressure plate 23 and work holder It are therefore likewise keyed together and consequently tilting of the connecting rod is because of misalignment of work holder and pressure plate is prevented.

If desired, pressure plate 23 may be raised and lowered from the work by means of an air or hydraulic cylinder. Such cylinder is shown in fragmentary form at 35 in Fig. 2, the cylinder being mounted on a cross bar as of the frame member of the lapping machine so as to be held substantially rigidly in place. The cross bar may be of the form shown in a copending application of Earl J. Bullard, Serial No. 14,619, filed March 12, 1948. The rod 3i operated by cylinder 35 is attached to pressure plate 23 in any suitable manner so that when the cylinder is operated and the piston rod 3'3 is raised, pressure plate 23 will likewise be raised off the work.

The number of connecting rods which may be lapped at the same time depends entirely upon the size of the ring l2 and lap iii. In the form chosen for illustration, provision is made for lapping fifteen connecting rod ends simultaneously in one ring. In the machine mentioned in the aforesaid Roshong application, four such rings are disclosed so that a total of sixty connecting rod ends may be lapped simultaneously in a machine equipped with fixtures hereinabove disclosed.

Inasmuch as the connecting rod straps or caps are substantially the same shape as the ends of the connecting rods themselves, the same work holder l6 may be used for lapping the split surfaces of the straps or caps, but in view of the low height of each strap, it is not necessary to use an apertured pressure plate such as 23. A solid disc separated from. the straps by a layer of felt or other soft pad will suifice (also as shown in the aforesaid Bullard application).

It is understood that the foregoing description is illustrative of preferred embodiments of this: invention and that the scope of the invention is not to be limited thereto, but is to be determined by the appended claims.

What is claimed is:

1. Apparatus for lapping the ends of connecting rods and the like comprising a rotatable lap plate having a lap surface, a conditioning ring having a surface thereof in. engagement with the lap surface of the lap plate and adapted to condition the latter, means operatively connected to the lap plate for rotating the latter, means holding the conditioning ring on the lap plate against bodily movement around the axis of the lap plate while permitting rotation of the ring about its own axis due to frictional contact thereof with the lap surface, awork holder disposed within the conditioning ring and in contact with the lap surface, there being a plurality of workreceiving openings in said work holder adapted to receive therein the ends of the-connecting rods tobe'lapped with the axes of the rods extending vertically, a pressure plate disposed Within'said conditioning ring above-said work holder, there being a series of clearance holes in said pressure plate through which the vertically extending connecting rods are adapted to pass when the rods are in lap-ping position on the lap surface, and a series of pressure pins depending from said pressure plate, each adapted to bear against a surface of a connecting rod to hold the same on the lap surface against tilting movement.

2. Apparatus for lapping the ends of connecting rods and the like comprising a rotatable lap plate having a lap surface, a conditioning ring having a surface thereof in engagement with the lap surface of the lap plate and adapted to condition the latter, means operatively connected to the lap plate for rotating the latter, means holding the conditioning ring on the lap plate against bodily movement around the axis of the lap plate while permitting rotation of the ring due to frictional contact thereof with the lap surface, said lap surface being adapted to receive thereon the ends of the connecting rods to be lapped with the rods projecting vertically upward therefrom, a pressure plate disposed within said conditioning ring above said lap surface, there being a series of clearance holes in said pressure plate through which the vertically extending rods are adapted to pass when the rods are in lapping position on the lap surface, and a series of pressure pins depending from said pressure plate each adapted to bear against a surface of a connecting rod to hold the same on the lap surface against tilting movement.

3. Apparatus for lapping the ends of connecting rods and the like comprising a rotatable lap plate having a lap surface, a conditioning ring having a surface thereof in engagement with the lap surface of the lap plate and adapted to condition the latter, means operatively connected to the lap plate for rotating the latter, means holding the conditioning ring on the lap surface against bodily movement around the axis of the lap plate while permitting rotation of the ring due to frictional contact thereof with the lap surface, a work holder disposed within the conditioning ring and in contact with the lap surface, there being a plurality of work receiving openings in said work holder adapted to receive therein the ends of the connecting rods to be lapped with the axes of the rods extending vertically, a pressure plate disposed within said conditioning ring above said work holder, there being a series of clearance holes in said pressure plate through which the vertically extending connecting rods are adapted to pass when the rods are in lapping position on the lapping surface, a series of vertically disposed pressure pins slidably mounted in said pressure plate each adapted to bear against a surface of a connecting rod to hold the same on a lap surface against tilting movement, and spring means efiective between each pressure pin and the pressure plate for absorbing the vertical thrust of said pins when the latter are in contact with their respective connecting rods.

4. Apparatus for lapping the ends of connecting rods of the type having flanged arch portions and bolt holes extending through the flanges thereof comprising a rotatable lap plate, a conditioning ring having a surface thereof in engagement with the lap surface of the lap plate and adapted to condition the latter, means operatively connected to the lap plate for rotating the latter, means holding the conditioning ring on the lap plate against bodily movement about the axis of the lap plate while permitting rotation of the ring about its own axis due to frictional contact thereof with the lap surface, a work holder disposed within the conditioning ring and in contact with the lap surface, there being a plurality of work receiving openings in said Work holder adapted to receive therein the ends of the connecting rods to be lapped with the axes of. the rods extending vertically, apressure plate disposed within said conditioning ring above said work holder, there being a series of clearance holes in said pressure plate through which the vertically extending connecting rods are adapted to pass when the rods are in lapping position on the lap surface, and a series of pressure pins yieldably mounted on said pressure plate and depending therefrom, said pins having tapered ends receivable in the bolt holes of the connecting rods to be lapped to maintain the same on the lap surface against tilting movement.

5. Apparatus for lapping the ends of connecting rods and the like comprising a rotatable lap plate having a lap surface, a conditioning ring having a surface thereof in engagement with the lap surface of the lap plate and adapted to con dition the latter, means operatively connected to the lap plate for rotating the latter, means holding the conditioning ring on the lap plate against bodily movement about the axis of the lap plate while permitting rotation of the ring about its own axis due to frictional contact thereof with the lap surface, a workholder disposed within the conditioning ring and in contact with the lap surface, means establishing a positive driving connection between said work holder and the conditioning ring while permitting relative vertical movement of the Work holder relative to the conditioning ring, there being a plurality of work receiving openings in said work holder adapted to receive therein the ends of the connecting rods to be lapped with the axes of the rods extending vertically, ,a pressure plate disposed within said conditioning ring above said work holder, means establishing a positive drive between said pressure plate and the work holder, there being a series of clearance holes in said pressure plate through which the vertically extending connecting rods are adapted to pass when the rods are in lapping position on the lap surface, and a series of pressure pins depending from said pressure plate, each adapted to bear against a surface of a connecting rod to hold the same on the lap surface against tilting movement.

6. Apparatus for lapping the ends of connecting rods and the like comprising a lap plate having .a lap surface rotatable about a vertical axis, means operatively connected to the lap plate for rotating the latter, a work holder offset radially from the vertical axis of the lap plate and in contact with the lap surface of the lap plate, there being a plurality of work receiving openings extending through the Work holder for receiving therein the ends of the connecting rods to be lapped with the axes of the rods extending vertically, a pressure plate disposed above said work holder, there being a series of clearance holes in said pressure plate through which the vertically extending connecting rods are adapted to pass when the rods are in lapping position on the lap Number Name Date surface, and a series of pressure pins yieldably 1,344,399 Holt June 22, 1920 mounted on said pressure plate and depending 1,592,105 Harris July 13, 1926 therefrom, said pins having tapered end receiv- 1,594,161 Evans July 2'7, 1926 able in the bolt holes of the connecting rods to 5 2,495,600 Ramsay June 24, 1950 be lapped to maintain the same on the lap sur- 2,539,561 Wolfskill Jan. 30, 1951 face against tilting movement, and means for 2,565,590 Bullard Aug. 28, 1951 preventing the pressure plate from revolving about the axis of rotation of the lap plate. FOREIGN PATENTS FRED L WHITE 10 Number Country Date 316,017 Italy Mar. 14, 1934 References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,339,047 Vincent May 4, 1920 15 

